I was extremely surprised when she told me. At first I didn't even realize what it was, because I hadn't seen the drawing since I was 11.

My grandparents gave them to all of my cousins and everyone as Christmas presents.

In fifth grade, my art teacher had our entire grade draw pictures of insects. She submitted all of the drawings (to Save the Children) and told us how whatever products they sell raises money for children all around the world who are in need of financial help.

It is true I had been successful on a small scale in overcoming one of the main difficulties in the new process, but there was still much to invent, and much that at that period I necessarily knew nothing about.

In such a case secrecy must be absolute to be effective, and although mere vague curiosity induced many persons of my intimate acquaintance to ask to be allowed to just go in and have a peep, I never admitted anyone.

The bronze powder business, however, no longer required my personal attention, and was well managed by those I had chosen as the guardians of a secret, which was long and honourably kept.